add missingConroller and missingAction method

[cebe]

fixes #754

[coveralls]

Coverage remained the same when pulling 2144049 on cebe:missing-action into dd90898 on yiisoft:master.

[coveralls]

Coverage decreased (-0%) when pulling bf24b45 on cebe:missing-action into dd90898 on yiisoft:master.

[qiangxue]

Line 621 should also be modified similarly.

[cebe]

This is line 621 :)

[qiangxue]

Please do not merge this PR until the discussion in #754 is finalized.

[cebe]

Yes, of course it was meant as a proposal only, should have made that clear in PR message.

[cebe]

Closing as this can better be done by overriding yii\base\Module::runAction on module or application level.